About a year ago, my wife's 2013 Edge starting having issues when going uphill. It's hard to describe, but basically as you started uphill the car would begin shuddering. It was as if it couldn't find the right gear, or wasn't getting gas, or something (sorry to be so vague, but I'm by no means a car expert). We took the car back to the CarMax where we bought, they ran diagnostics and couldn't find anything wrong. Took the car home and a week later it started again, only worse. Went back to CarMax, diagnostics still couldn't find anything wrong, but at least this time it would misbehave when the technician drove it. They even took it to a Ford dealership and they couldn't find anything wrong. After a week without the car, they ended up replacing the coils and the issue seemed to go away.
Now fast forward almost a year to this week. My wife is driving to work and the same thing happens. Actually happened in the exact same place where it started misbehaving a year ago. I meet her and swap cars, and this time I take it to my local Ford dealer. During the trip to the shop, it only acted up with me one time. The technician takes a look, and just like before, diagnostics doesn't show anything and it didn't act up with them when they took it for a test drive. They ended up installing a software update, but told us that they weren't really sure if that would fix the problem.
So my question is, has anyone experienced this before, and is it common in the Edge? If you have experienced it, what was the root cause of the issue? We're wondering if maybe we just got a lemon and should trade it in.
Any help is greatly appreciated.
Thanks